Hydraulic motor



5 Sheets-Sheet 1 v F. A. GRUETJEN HYDRAULIC MOTOR Filed May 7, 1938 March 5, 1940.

FIG. I.

INYENTOR. BY mm ATTRNEY.

. Mardi 5, 1940. F,A GRUETJEN 2,192,402

HYDRAULIC MOTOR Filed May '7, 1938 3 Sheets-Sheet 2 2 u n* i ill 1 -Lfz /z -I- -i/z 131- is 131 if mh I3 1N VENTOR.

ATTORNEY.

March 5, 1940. F, A, GRUETJEN 2,192,402

HYDRAULIC MOTOR Filed May '7, 1938 3 Sheets-Sheet 3 ATTORNEY.

Patented Mar. 5, 1940,

UNITED STATES 1 .,T1:NT OFFICE 2,192,402 HYDRAULIC MOTOR Application May 7, 1938, Serial No. 206,541

1 claims. Y (c1. 121-158) This invention relates to draulic motors.

An object of the invention is to provide an improved hydraulic motor of the reciprocating type. L

Another object of the invention ,is to provide an improved reversing valve for controlling the distribution of power uid to the cylinder of a reciprocating hydraulic motor.

Further objects o f the invention will be clear from the accompanying description and the drawings in which:

Figure 1 is a -view showing a longitudinal section through the cylinder of a hydraulic motor and its reversing valve embodying the invention,- and also representing diagrammatically the various fluid conduits which connect the different ports inthe cylinder of the motor and. the body of the reversing valve;

Fig. 2 is a longitudinal section through the reversing valve similar to the viewl shown in Fig. 1 but with the pilot valve and *main valve in opposite positions from those which they occupy in Fig. 1;

Fig. 3 is a longitudinal section on the line 3-3ofFig.5; M I,

Fig. 4 is a longitudinal section on theline 4 4 of Fig. 14;

Fig. 5 is a top plan View of the reversing valve;

Figs. 6 to 13 inclusive are transverse vsections reciprocating hytaken through the reversing valve on their rev spective section lines as indicated in Figs. 1, 3

and 4 of the drawings;

' lig. 14 is a bottom view of the reversing valve;

Fig. 15 is a longitudinal section through a deep well pumping unit which employs a hy draulic motor to drive a reciprocatingp Referring to the drawings. and in ,particular to Figs. l and 2, the hydraulic motor comprises a piston l in a cylinder 2 which is connected by suitable ports and iiuid conduits to revers valve 3. The reversing valve has two piston valves sliding in their respective bores in valve body Li, these valves being pilot valve and main valve E. Fluid conduits shown schematically on Figs. 1 and 2 as l, S, 9 and it connect ports Il, I2, l3and is in the `cylinder oi the hydraulic motor to ports I5, I6, il and I respectively in the body of the reversing valve. Ports il and ifi and their connected conduits 'l and it serve to admit powerliluid to and to exhaust it from the two ends of the hydraulic cylinder 2. Ports I2 and I3 and their associated iiuid conduits 8 andtareusedtoreversethe pilotvalveand consequently the main valve and the piston I of the hydraulic motor when the piston passes over one or' the other of ports I2 and I3 during the course of its motion toward the vrespective end of cylinder 2. Power iiuid for actuating the hydraulic motor is led to valve port I9 through uid conduit 20. Conduits 2l and 22 conduct the power uid exhausted from the motor away from valve ports 23 and 24. Conduits 25 and 26 connect ports 2l and 28 respectively to the lo lower and upper ends 29 and 30 of the cylin, drical bore in which the main piston valve 6 slides; Fluid passageways 3l, 32,- 33, 34 and 35 cut in th'e valve body establish communication respectively between the following pairs of ports, 15 36 and 4I, 31 and 23, 33 and I9, 39 and 26 and l and 62, of which the rstport in each pair opens into the bore for the main valve and the second into the bore forv the pilot valve.,

Whenthe pilot valve 5 has the position shown g@ I in Fig. 1, power :liuid from conduit 2li is conducted through ports'v 'I9V and 2l and conduit 25 to the lower end 29 of the bore which houses the main valve 5. The upper end 30 of this bore is connected through conduit 26 and ports- 25 28 and 2K5v to conduit 22 for receiving the fluid discharged from the hydraulic motor. Since both )the main valve and the pilot valve are piston valv they are balanced except against ldii'erences of pressure which may em'st across 3@ their ends, and the greater pressure on the lower end of main valve 6 will therefore hold it securely in its extreme upper position. When the main valve is in this position, power fluid from conduit 2t is conducted through port is, 35

geway 33, ports 38 and i5, conduit l' and port l@ tothe lower end oi the cylinder of the hydraulic'motor. Port ld at `the upper end of the cylinder' counicates through conduit it, ports .i3 d 3Q, passageway 35% and port 2t M, with conduit 22 for the reception of exhaust uid from the hydraulic motor. Under these conditions the piston of the motor is driven upwardly as indicated by the arrow in Fig. 1.

The upper end d3 of the bore which houses the pilot valve communicates through slot tl in the pilot valve, passageway 35, ports d@ and il, huid conduit t and port I3 rwlththe upper end of the cylinder of the hydraulic motor. The

hydraulic motor and is substantially the pressure of the surrounding atmosphere. There is consequently, substantially no excess of pressure lexerted on the upper end of the pilot valve 5 to shift it from the position shown in Fig. 1. A 55 pressure here is the exhaust pressure of the y body 'through conduit 20.

spring'detent 45 is provided at the upper end.

of the pilot valve, and a hydraulic lock 46 at the lower end to hold the pilot valve in position against the force of gravity, and also to insure that the pilot valve will not be thrown by small pressure fluctuations but only by the application of a pressure change exceeding some desired value which is determined by the-construction of the spring detent andthe hydraulic lock.

'I'he valve operates to reverse' the motion of the hydraulic motor according to the following `sequence of events. Continued upward motion of the piston I as indicated in Fig. 1 first causes the piston to cover port I3 and to then uncover it, exposing it to the high pressure uid which is in the lower. endof the cylinder. This high pressure is transmitted. through conduit 9, ports I1 and 40, fluid passageway 35 and slot 44 to the upper end of the pilot valve 5. Acting on this end of the valve the high pressure forces it:

down against the opposition offered by the spring detent and the hydraulic lock 46, the construction and operation of which will be explained in detail hereinafter. When the pilot valve moves down, the lower end 29 of the main valve bore is connected through conduit 25 and ports 21 and 23 to the discharge pressure in conduit 2l. The upper end 30 of the main valve bore is connected through conduit 26 and ports 28 and I9 to the poweriluid entering the valve The main valve is therefore forced down in which position it reverses the ow of fluid through conduits 1 and I0 and consequently reverses the motion of the piston in the hydraulic motor.

Restricted passageways or fluid chokes 41 (Fig. 4) are provided in iiuid conduits 25 and 26 to throttle the flow of iiuid through them and prevent a violent shift of the main valve 6 from one end of its bore to the other. Suitable slots 48 are provided on the main valve 6 to insure a gradual reversal of the piston in the hydraulic motor, and to maintain suncient pressure in the valve ports during reversal to insure that reversal of the valves will take place.

'I'he hydraulic lock indicated generally at 46 comprises a cylindrical bore 49 in the pilot valve and a valve seat 50 in a bushing 5I which makes a tight t in the cylindrical bore 49 and is held in place by a rivet 52. A central opening 53 and vent holes 54 provide fluid passageways leading from the valve seat to the space below the pilot valve. A plunger 55 is pressed against valve seat 50 by a spring 56. Holes 51 and 58 bored in the pilot valve provide communication between spaces 59 and 60 and ports 3I and 32. A slot 6I provides for a fluid passageway between spaces 59 and 62.

When the pilot valve has the position shown 'in Fig. 1, spaces 59, 60, and 62 are in communication with the discharge pressure from the motor. Since this pressure is substantially that of the surrounding atmosphere it has no resultant reilfect tending to shift the plunger 55 in one direction or the other. 'I'he plunger is held tightly pressed against the valve seat 56 by spring 56. Space 63 below the pilot valve is lled withfluid as a result of the previous cycleof operations and as t a consequence the pilot valve cannot move down so long as plunger 55 remains on its seat 50 and prevents egress of iiuid from space 63. Consequently slight pressure fluctuations -or 4small forcs are incapable of moving the pilot valve down. When, however, the piston in the hy draulic motor passes over port 9 and admits high pressure iluid to the upper end of the pilot valve as previously described, the force is sumcient to drive the valve down, the Huid trapped in space 63 unseating plunger 55 against the pressure o f spring 56 and escaping through slot 6I, space 59 and hole 51 to passageway 3I and. from there v through ports 36 and 31, passageway 32 and port -against the resistance offered by spring detent 45. In this position also the hydraulic lock operates to hold the pilot valve locked in position against small forces or fluid pressures which' might otherwise move it to the other end of its bore. When, however, the motion of the piston in the hydraulic motor carries it below the port I2, high pressure fluid is admitted to space 59, through a path readily traced on the drawings. This high pressure iiuid acts on the annular area between the valve seat 50 and the cylindrical bore in which plunger 55 slides, forces the plunger upward against the force exerted by spring 56, and passes through the opening 53 to the space 63 below the ,pilot valve where` it exerts a force which shifts this upward against the resistance offered b y the spring detent 45. The main valve is then thrown up by the action of the pilot valve, and the piston of the hydraulic motor is reversed.

The course of the passageways and conduits provided in the valve body can be followed in Figs. 3 to 14 inclusive in which/the passageways and conduits have been identified by the same numerals used in Figs. 1 and 2.

Fig. 15 illustrates an application -of the improved hydraulic m'otor and reversing valve of this invention in connection with a deep well pumping unit for pumping crude oil or other uid from a well. 'I'he pumping unit indicated generally by the numeral 64 comprises an electric motor 65; a pump 66 connected to the electric motor for supplying power iiuid to operate a hydraulic motor; a sump or reservoir 61 from which the pump 66 takes oil and into which the discharge from the hydraulic motor is returned;

a hydraulic motor consisting of a reversing valve 3 and cylinder 2 with piston I and piston rod68; and a crude oil pump 69 in which the piston rod of the hydraulic motoracts as the plunger. In the embodiment illustrated the power oil which circulates through pump 66 andthe hydraulic motor does not come in contact withl the crude oil pumped from'the well and can 'be` kept free from sand and grit or other substances which would injure the mechanism. A tubing string 10 is provided to conductv the crude oil '0 the surface, and an electric cable 1I to conve( the electric motor. A

In some cases it may be desirable to have pump y power to 66 and its electric motor located at the surface of L the ground from whence they supply power fluid for the operation of the hydraulic motor through hydraulic tubing running from the surfacev of the ground to the submerged pumping unit. The

power fluid discharged fromthe hydraulic motor can be conducted to the surface through another string of tubing in case it is desired to recirculate it and keep it free from admixture-withV the crude oil`pumped from the well. In other cases it may be preferred to lead the discharge from the hydraulic motor directly to the tubing used to carry the crude oil to the surface. This makes it possible to dispense with one string Dftubing. When this is done fresh power fluid must be supplied continually to replace that which passes through the hydraulic motor and is then discharged into the crude oil line. 'I'his can frequently be a part of the crude oil pumped which is ltered and otherwise cleaned to remove substances which might have a deleterious effect upon the hydraulic motor. y

The invention may have various embodiments within the scope of the following claims.

I claim:

1. In a valve structure for controlling the distribution of power fluid to the cylinder of a reciprocating hydraulic motor, the combination of a main valve for operating said motor, a pilot valve for controlling the main valve, means for admitting fluid under pressure to the pilot valve to shift it from one position to another, and hydraulic means for locking the pilot valve in position until the pressure of the fluid tending to shift it exceeds a predetermined value.

2. A hydraulic motor comprising a cylinder, a piston reciprocable therein, a fluid passageway connecting each end of the cylinder to the bore of a main valve for controlling the flow of fluid to and from the cylinder of the hydraulic motor, a main valve movable within the main valve bore, a bore for a pilot valve, a pilot valve movable therein, means actuated by the pilot valve for shifting the main valve, a port to each side of the center of the main cylinder traversed by the piston in its travel, uid passageways connecting said ports to the bore of the pilot valve, and resilient ,means preventing flow of fluid in such passageways unless the pressure which tends to cause. said ow `exceeds a predetermined value.

3. In a hydraulic motor comprising a cylinder, a piston, and a main valve actuated by a pilot valve, the combination of a pilot valve bore, a pilot valve reciprocable therein, ports within the pilot valve bore to control the iiow of fluid through the pilot valve to an end of the pilot valve bore Where it would exert a. pressure upon the pilot valve tending to shift it from this end of the bore, and resilient means carried by the pilot valve for preventing such ow of fluid through it when the pressure tending to cause said ow is less than a predetermined value.

4. In a valve structure for controlling the distribution of power fluid to the cylinder of a reciprocating hydraulic motor, the combination of a main valve for operating said motor, 'a pilot valve for controlling the main valve, means for admitting iluid under pressure to the pilot valve to shift it from one position to another, and spring-pressed hydraulically operated means for locking the pilot valve in position, said last named means being responsive to the pressure of the uid tending to shift the pilot valve for releasing the lock.

FREDERICK A. GRUETJEN. 

